1. Field of the Invention
The present invention relates to a method and apparatus for decoding a physical or electronic code image, and more particularly, to a method and apparatus for decoding a code that is a combination of at least two code images (hereinafter referred to as a “mixed code”).
2. Description of the Related Art
Recognizable information, such as a character, a number, and a sign, may be expressed as an image in consideration of the security of the information and a space in which the information is to be displayed. To interpret such an image (code image) containing information, a decoder is required.
The code image may be a one-dimensional barcode such as a universal product code (UPC) and an European article number (EAN), and a two-dimensional code such as a color code, a gray code, a quick response (QR) code, a PDF-417 code, and a data matrix. Information may be obtained by recognizing an image and extracting the information from the image using watermarking designed by MarkAny and a technology of recognizing a logo of an image.
Since the image code conceals information and information regarding the code is not disclosed, a user may have difficulties in using the image code. For instance, the user cannot predict whether the image code is available to a general mobile terminal or a personal digital assistant (PDA), whether the image is provided from a personal computer (PC), and whether information is contained in the image code. Also, the amount of data that can be expressed using each code is limited. Thus, in general, an image code must be newly produced whenever data is updated, and it is difficult to include information indicating whether the data is updated into the image code.
In general, watermarking is used to determine whether a user who desires to use an image is an authorized user or has a copyright of the image, or provide network connection services using image information. Therefore, watermarking information is contained in an image not to be disclosed, and is not related to information regarding the image. Even if the watermarking information is related to the information regarding the image, it is impossible to decode the image using the watermarking information. Of course, a watermark can be embedded into a code image, but in this case, the watermark is just combined with the original code image to make a simple combination thereof.
The color barcode is manufactured by mapping colors to a barcode pattern. Although the number of ways to express information can be increased through the color barcode, the color barcode is also a simple combination of the colors and the barcode pattern.
Alternatively, an image can be recognized by a trademark, a logo, or a pattern. In detail, an input image is recognized by preparing a database of a pattern of a specific image, and comparing the input image with a specific image from the database to determine the similarity between the images.